The semiconductor industry has seen a remarkable miniaturization trend, where the size of microelectronic circuit components is expected to reach the scale of atom even subatom. Here, an orbital switch formed at the interface between BaTiO₃ (BTO) and La_0.5Sr_0.5MnO₃ (LSMO) is used to manipulate the electric field effect in the LSMO/BTO heterostructure. The orbital switch is based on the connection or breakdown of interfacial Ti–O–Mn bond due to the ferroelectric displacement under external electric field. This finding would pave the way for the tuning of the material performance or device operation at atomic level and introducing the orbital degree of freedom into the terrain of microelectronics.

Electrical manipulation of lattice, charge, and spin is realized respectively by the piezoelectric effect, field-effect transistor, and electric field control of ferromagnetism, bringing about dramatic promotions both in fundamental research and industrial production. However, it is generally accepted that the orbital of materials are impossible to be altered once they have been made. Here, electric field is used to dynamically tune the electronic-phase transition in (La,Sr)MnO₃ films with different Mn⁴⁺/(Mn³⁺ + Mn⁴⁺) ratios. The orbital occupancy and corresponding magnetic anisotropy of these thin films are manipulated by gate voltage in a reversible and quantitative manner. Positive gate voltage increases the proportion of occupancy of the orbital and magnetic anisotropy that were initially favored by strain (irrespective of tensile and compressive), while negative gate voltage reduces the concomitant preferential orbital occupancy and magnetic anisotropy. Besides its fundamental significance in orbital physics, these findings might advance the process towards practical oxide-electronics based on orbital.

The requirement for high-density memory integration advances the development of newly structured spintronic devices, which have reduced stray fields and are insensitive to magnetic field perturbations. This could be visualized in magnetic tunnel junctions incorporating anti-ferromagnetic instead of ferromagnetic electrodes. Here, room-temperature anti-ferromangnet (AFM)-controlled tunneling anisotropic magnetoresistance in a novel perpendicular junction is reported, where the IrMn AFM stays immediately at both sides of AlO_x tunnel barrier as the functional layers. Bi-stable resistance states governed by the relative arrangement of uncompensated anti-ferromagnetic IrMn moments are obtained here, rather than the traditional spin-valve signal observed in ferromagnet-based tunnel junctions. The experimental observation of room-temperature tunneling magnetoresistance controlled directly by AFM is practically significant and may pave the way for new-generation memories based on AFM spintronics.

The electronic phase transition has been considered as a dominant factor in the phenomena of colossal magnetoresistance, metal-insulator transition, and exchange bias in correlated electron systems. However, the effective manipulation of the electronic phase transition has remained a challenging issue. Here, the reversible control of ferromagnetic phase transition in manganite films through ionic liquid gating is reported. Under different gate voltages, the formation and annihilation of an insulating and magnetically hard phase in the magnetically soft matrix, which randomly nucleates and grows across the film instead of initiating at the surface and spreading to the bottom, is directly observed. This discovery provides a conceptually novel vision for the electric-field tuning of phase transition in correlated oxides. In addition to its fundamental significance, the realization of a reversible metal-insulator transition in colossal magnetoresistance materials will also further the development of four-state memories, which can be manipulated by a combination of electrode gating and the application of a magnetic field.